Many height adjustable baby mattress supports are known in the prior art. The most commonly available height adjustable baby crib is one that requires manual disassembly of at least a portion of the crib main frame and of components such as brackets that attach the mattress support to the main frame. After the mattress support is positioned at a desired height, the brackets and main frame have to be reassembled.
Such types of baby cribs suffer from several disadvantages:    1. It is necessary to assemble and disassemble the main frame and mattress mattress support to accommodate the growth of the baby, causing user discomfort during a time consuming and awkward assembly operation.    2. When a baby needs to be diapered, cared for, or dressed, the attendant has to bend over the upper railing of the crib in order to access the baby. Intermittent bending motions of the attendant result in back pains since the mattress support is positioned at a set height, and it is inconvenient to change the height of the mattress support.    3. The main frame of prior art cribs is generally configured with means to set the mattress support at one of a predetermined number of height levels, e.g. three different height levels. Many attendants are desirous of setting the mattress support at one or more different levels.
Various continuously height adjustable baby mattress supports are also known in the prior art; however, the associated apparatus for adjusting the mattress support height is a relatively complex mechanism.
U.S. Pat. No. 2,599,296 discloses an adjustable crib spring which is arranged to be raised and lowered, two pairs of geared levers at each end of the crib and provided with tension springs to tend to draw them together to raise the crib spring, handles on the crib spring for manual movement of the latter, and catches on the crib. One lever at each end of the crib is connected to a corresponding lever at the other end of the crib by means of a shaft so that the levers are forced to move together and that tilting of the crib spring is prevented.
U.S. Pat. No. 4,285,079 discloses an apparatus by which a mattress support is raised and lowered by flexible hoist members attached to a winding bar that is rotatably journaled in two housings. The hoist members are threaded through the housings and attached to the winding bar. At their ends, the hoist members are secured by brackets to a spring frame that forms part of the mattress support.
IT 1238733 discloses a child's bed having a manually moveable mattress frame with a spring and gas piston system for guidance and counterweight.
GB 2422303 discloses a cot with a height-adjustable mattress base. Support means are provided taking the form of scissor-pivoted leg members. A switch controlling a linear actuator causes the leg members to be pushed open to lower the mattress or pushed together to raise the mattress.
It is an object of the present invention to provide an uncomplicated apparatus for continuously adjusting the height of a baby mattress support that includes only a few parts.
It is an additional object of the present invention to provide an apparatus for continuously adjusting the height of a baby mattress support that is easy to operate.
It is an additional object of the present invention to provide an apparatus for continuously adjusting the height of a baby mattress support that occupies a minimal volume.
Other objects and advantages of the invention will become apparent as the description proceeds.